The test bench is designed to evaluate air-oil mist filtration performances of the filtration elements and vessel during time. The test bench has been designed to allow the testing of two different arrangement for the filter:

  • Configuration 1, the filter is tested in vacuum operation
  • Configuration 2, the filter is tested in pressure operation





To reproduce the real working conditions of the tested filters, the test bench has been designed to generate an oil mist that is dispersed into the air stream using an atomizer nozzle driven by compressed air.




The test bench has all the necessary equipment and instrumentations to allow the reliability and repeatability of the test. The test bench allows the remote control of the tests using the Control System that performs all the automatic controls, the main control loops are:

  • Air flow control, the flowrate is maintained constant using a flow transmitter that controls the inverter of the blower
  • Ait temperature control, the filter inlet temperature is maintained constant using a temperature transmitter that controls the heater of the air
  • Oil flowrate maintained constant using a liquid flow controller

The control System also performs the safety control loops in case of any malfunction, stopping the test and bringing the test bench in a safe state.


The test bench has air sampling points allowing the characterization of air-oil mist and the determination of number and mass separation efficiency.


Evaluable variables are:

  • Pressure drop versus time and flowrate
  • Coalescing filter elements saturation time
  • Determination of mass and number separation efficiency
  • Exit air quality with Draeger and spectrometers measurements
  • Characterization of oil-mist aerosol and relative numerical particle distribution at inlet and outlet of the filter